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4 Safety Function Blocks
NX-series Safety Control Unit Instructions Reference Manual (Z931)
4
SF_SafetyRequest
SF_SafetyRequest
This safety FB makes requests for the safe state and monitors the safety state for an actuator (e.g., a
drive or valve) that has a safety function.
Instruction Name FB/FUN Graphic expression
SF_SafetyRequest Safety
Request
FB
Variables
Input Variables
Variable Data type Valid range Default Description
Activate BOOL TRUE or FALSE FALSE Refer to Safety FB Common Input Variables on page 4-2.
S_OpMode SAFEBOOL TRUE or FALSE FALSE A variable. It is a request for the operation mode of the
connected actuator.
FALSE: Requests safe mode.
TRUE: Requests an operation mode (i.e., non-safe state).
S_Acknowledge SAFEBOOL TRUE or FALSE FALSE A variable. It is the response from the connected actuator
(to confirm whether the actuator is in safe mode).
FALSE: Operation mode (i.e., non-safe state).
TRUE: Safe mode.
MonitoringTime TIME Depends on data
type.
T#0s A constant. It inputs the monitoring time from the safe
mode request (i.e., from when S_OpMode changed to
FALSE) until the actuator response (i.e., when
S_Acknowledge changes to TRUE).
Reset BOOL TRUE or FALSE FALSE Refer to Safety FB Common Input Variables on page 4-2.
Output Variables
Variable Data type Valid range Default Description
Ready BOOL TRUE or FALSE FALSE Refer to Safety FB Common Output Variables on page
4-4.
S_SafetyActive SAFEBOOL TRUE or FALSE FALSE The actuator operation mode.
FALSE: Non-safe state.
TRUE: Safe mode.
S_SafetyRequest SAFEBOOL TRUE or FALSE FALSE The operation mode request to the actuator.
FALSE: Requests safe mode.
TRUE: Requests an operation mode (i.e., non-safe
state).
Error BOOL TRUE or FALSE FALSE Refer to Safety FB Common Output Variables on page
4-4.
SF_SafetyRequest
Activate
S_OpMode
S_Acknowledge
BOOL
SAFEBOOL
SAFEBOOL
BOOL
Ready
S_SafetyActive
S_SafetyRequest
Error
WORDDiagCode
BOOL
SAFEBOOL
SAFEBOOL
TIME MonitoringTime
BOOL Reset
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